Machine and method for feeding sheets



Dec. 2, 1958 P. D. LABOMBA-RDE 2,862,709

MACHTNE-IAND METHOD FOR FEEDING SHEETS Filed March 16, 1955 4 Sheets-Sheet 1 mll l l OOOOOIO IN VEN TOR.

PHILIP D. LABOJMBARDE Dec. 2, 1958 P. D. LABOMBARDE 2,862,709

- MACHINE AND METHOD FOR FEEDING SHEETS Filed March 16, 1955 I 4 Sheets-Sheet 3 Iii! lmlllllll'lllIIllllillllllllilllll ljlwillll milm 'll'l u I I iii INVENTOR. W PHILZPD. LABOMBARDE PM W ATTORNE'YS 4 Sheets-Sheet 4 L 4% 1 WM 9 4 2 F H 7 0 T W .8 w n 72 -/\2 m J F i n W W,

Dec. 2, 1958 I 'P. D. LABOMBARDE MACHINE AND METHOD FOR FEEDING SHEETS Filed Marcih 15, 1955 United States Patent MACHINE AND'METHOD FOR FEEDING SHEETS Philip Labombarde, Nashua, N. H. Application March 16,1955, Serial No. 494,731

12 Claims. (Cl. 271-32) 7 This invention relates to sheet feeding devices and especially to bottom feed'magazines used in paper box folding machines and the like. a

It has heretofore been proposed to apply the frict on surface of a moving feed member to the exposed surface of an endmost sheet in a stack in order to slide the sheet partly or. entirely oif the stack. Separator means is usually provided With such feeders including a passage oppositethe leading edge of the endmost sheet for passing only one sheet at a time while barring the advance of the next succeeding sheets. The leading portion of the sheet, moved through the passage by the friction feeder, usually passes into the nip of a pair of rapidly revolving rolls which completely draw the sheet from the stack and continue its forward movement. It has been the custom to return the friction surface to itsstarting point in a circular unidirectional path removed from the plane of the end blank orto otherwise keep the friction feed surface out of contact with the advanced sheet on' a return stroke to avoid returning the sheet to its starting position. It is an object of this invention to provide a friction feeding member which is substantially co-planar with an "ice 1 air pressure period, the gradual change therebetween and the dwell of the carriage at each opposite end of its stroke. 7

The feed end of one type of machine for folding or otherwise acting upon a plurality of fiat sheets is shown end-most sheet during a forward feeding stroke as well as during a rearward non feeding stroke and yet 'does not tend to return the advanced sheet to its starting position; Y

' 'Another object of the invention is the provision of a friction feeding member which reciprocates rectilinearly across the bottom of a magazine adhering tightly to the end-most sheet during a predetermined major portion of a forward stroke and not adhering thereto atall on the rearward stroke; 7 i

A further object of the invention is to providemeans for applying a friction feed surface fiatwise to the surface of a sheet with no sheet advancing; component, to ad- .vance the sheet only after a firm grip has been established by the feeder to prevent slippage and to operate the feeder only in a simple, straight line, path rather than around a circuitous path relative to the sheet.

Still'another object of'the invention is the provision of a friction feeding element in a bottom feed magazine which draws the surface of a sheet into firm-frictional contact therewith before, and continuously fora predetermined major portion-of a feed stroke but establishes a cushionof air between itself and the sheet o'n thereturn stroke, thereby lessening wear on the friction surface while continually supporting the stack in the magazine;

Other objects and advantagesaof the invention willbe 'apparent from thedrawings and the description thereof as well as from the claims appended hereto. 1 i

In the drawings: j a

Fig. 1 isa sideelevation, partly in section, of thefeed end of one typeof paper boxfolding machine showing the apparatus of this invention applied thereto. The suction grippers are shown in the early part oftheir feed stroke.

2 is'a' view similar to Fig. 1 showing'thesuction at 21, the remainder of the machine forming no part of this invention. A pair of upstanding side frame pieces 22 and-23 are connected transversely by cross supports such as 24 and the paper line of the machine is indi 'cated at 25. As is customary with such machines, the sheets are 'moved fiatwise and horizontally along the paper line 25 by suitable belts or chains while certain folding, glueing or other operations are performed thereon all in a manner well known in the trade. The machine 20 is power driven by any convenient means not shown and includes a drive chain 26 for driving the various parts of the machine in synchronization. As shown in Fig. 1 the apparatus of this invention is also driven by the chain 26 whereby it is similarly synchronized. The magazine means 27 illustrated is of the bottom feed type and includes a pair of upstanding side plates 28 and .29 for retaining an upstanding stack 30 of flat sheets such as 31. Sheets 31 may be paper box'blanks or any other type of sheet intended to be fed individually and sucessively from the end of a stack-by an endwise sliding movement. Preferably a rearwardly inclined plate 32 is provided in magazine means 27 for aligning and guiding the trailing edges of the sheets 31 and tending to incline the leading edges of the lower sheets in the stack 30. The bottom of magazine means. 27,as best shown in Fig. 3, includes at least two longitudinally extending rails or supports 34 and 35 forminga horizontal, anti friction surface for supporting the bottom sheet 36 and the stack 3%. Each rail 34 or 35 isvertically, slidable in a sleeve such as 37 or 38, thefsleeves being slidable laterally on a cross support such as 39. Suitable set screws are provided for varying the height and lateral positioning of the rails 34 and. 35 and preferablythe rails are located on opposite sides of the stack30 near the longitudinal edges of the sheets 31 therein. Preferablyalso, a centrally disposed, longitudinally extending support 42 is provided, support 42 having a line of rollers such' as at 43 and 44, each journalled as at 45 on one of the opposite sides of support 42. The top surfaces of the rollers in lines 43 and 44 are co-planar with the top surfaces of rails 34 and 35 to form a flat, substantially frictionless bottom to the magazine means 27. Support 42 is mounted on cross members 46 and 47 and extends forwardly to proximate the nip of a pair of rolls 48 and .49 thereby forming a fixed platform 50 for guiding each 'mounted in gate member 54 and operable against block 57 to permit adjustment of the height of the gate member.

'The'terminal tip 62 of gate member 54 may thus be spaced exactly the thickness of a single sheet from the platform 50 to form a sheet separator passage while the portion 60 prevents the passage of the next succeeding sheet or sheets.

The friction feed means of the invention includes a. fiatfriction surface co 'planar with the undersurface63 :of the bottom sheet 36 of'the-stac'k- 30 and preferablyformed by the rims of a plurality of suction, grippers :suehas 64, 6 5,; 66 and '67. Each grippersuchas 64 is preferably formedby a -metal housing 68, an annularjfrictionrim 69 of rubber or the like and a central opening 70 through which air may be blown or withdrawn; Each housing 6 8 -;includesa bracketsuch as 71'having holes such as 72 for screwssnch as 73 whereby. it may be fixed'to a carriage 74. Carriage 74 is slideable longitudinally in straight grooves orjtracksi75 and 76in the support 42, the grooves -75 and 76 'beingparallel to the plane of the bottom sheet -36.= Thusthe carriage-Hand the flat friction surface'formed :by rims 69 may 'be moved longitudi nallyforwardly' and rearwardly relative to stack 30 with the rims 69' continuously level and in engagement with the undersurface 63 of -the bottom sheet 36. Feeding mechanism is provided including alaterally projecting lug 78 embracedby the elongated slot 79 formed in the bifurcated end 80-of a bell crank lever 81. Lever 81 is pivotedat 82 on atransverse shaft 83 and carries a roller cam follower 84 at its other terminal end. Follower- '84is engaged'in the path 85 of a continuously rotatingrpath-cam 86 fixed to a transverse shaft 87. Shaft 87 also carries a sprocket 88, the sprocket being driven by;the drive chain 26. As best shown in Fig. 1 chain 26 also drives a sprocket 90 on the shaft 91 which carries roll 49 whereby the feed rolls 48 and 49 and the friction feed mechanism are synchronized. A suitable idler sprocket 92" and tension sprocket 93 are also provided for chain 26.

The' suction means of the invention includes flexible pipes or conduits such as 94, 95, 96 and 97 connecting the openings 70 of each suction gripper to a distribution pipe 98 fixed to the machine by a bracket 99. Distribution pipe 98 is' connected by a pipe 101 to a port 102 of a control valve 103, valve 103 having a chamber 104 for a sliding piston head 105. Another port 106 of valve 103 is connected by a pipe 107 to an air exhaust tank 108 the tank'108 being exhausted of air to create continuous suction by a suitable pump not shown and well known in the art.

Pneumatic means is provided including an air pressure pipe 110'from any suitable source of air pressure such as an air pump and tank or from the air pressure supply usually found in factories using machines of the'nature 'of this invention. Pipe 110 leads to a third port 111 in valve 103 in order that by movement of-head 105 either air pressure or suction may be applied to the pipe 101 leading to the suction grippers. The piston head 105 of valve 103is slideable 'by a piston: rod-112 carrying a roller-carnfollower 113 at its opposite end and follower 113-is in engagement with thesurfa'ce 114 of a-cam 115 mounted'on shaft 87. Thus-the control valve 103 is operably connected to the friction-feed mechanism, the 7 rolls =48 and'49 and the other operating partsof the machine.

In operation, a stack of'sheets, boxblanks or the like are placed in the magazine -means so that the bottom sheet 36 rests on the rails 34 and 35, on the lines of rollers 43 and 44 and on the rims 69 of the suction grippers '64; 65, 66, and 67. The sheet passage of the separatormeans formed by member 48 and platform is adjusted to pass only one sheet at a time. The carriage 74 then commences to reciprocate forwardly. toward the sheet passage and rearwardly away from the sheet passage with the rims 69 of the suction grippers at all times coplanar 'with the bottom of the magazine means and the undersurface 63 of each successive endmost sheet. At

the rear point'of the stroke of the carriage 74,- when the carriage is Temporarily haltedto' changedirection," the van/e103 causes full suction to beapplied'to th'esuc- 4 tion grippers. The bottom sheet 36 is thus pulled tightly onto the friction rims 69 to increase the friction and assure a grip without slippage. Carriage 74 then advances in a feeding direction, with the full suction still applied whereby the suction grippers slide the bottom sheet along rails 34 and 35, partially off the bottom of the stack. The leading edge portion: 1160f the bottom sheet 36 passes throughlhe sheet passagev and into the nip 51 of the ro'lls'48'and 49. The'continuously rotating rolls 48 and 49 then seize the sheet and continue its advance completely ofi the stack'and further along the paper line 25. The stroke of the carriage is longer than the distance between the sheet separator passage and the nip of the rolls 48 and 49 and full suction is released'just as the leading edge of the sheet is gripped by the rolls to avoid damage to the sheet or to the feed mechanism. At the forward point of the stroke of carriage 74, when it has halted to change direction, the control valve 103 has already move-d piston head 'to close the suctionport 106and .open pneumatic, or air pressure, port 111. Thus the bottom sheet 36, andeach successive bottom sheet is moved exactly the same distance by carriage 74, namely from gate tip 62 to roll nip- 51 and the rolls 48 and 49 continue-the-advance of the sheet .in exact registration with the machine; The air under pressure blown through pipes 94, 95, 96 and 97 completely releases any adhesion between the sheet 36 and the friction rims69 of the suction grippers and the sheet may be advanced by the rolls 48 and 49 while'supported only on. the rails 34'and 35, the line of rollers 43 and 44 and the air cushion formed above each suction gripper. On the return stroke of the carriage .74 to engage and feed the next succeeding bot tom sheet, air is continually blownthrough the openings 70 of the suctiongrippers toeliminate any tendency of the grippers to return the sheet just advanced to its starting position.-

It should be noted that no spring is required to main tain the follower 113 of valve 103 in contact with the surface of cam 115. This is because air pressure from port 111 pushes the piston head 105' toward the cam or suction'from' port 106 'pulls the piston-head 105 toward the cam at all times. It should also be-noted that no paper dust is likely to clog the suction mechanism since there'is no motion of air in the grippers and pipes when suctionis on; In addition, because of the alternate blowing of air through thesuction'mechanis'm dry paper dust is cleared automatically from the mechanism by the outward motion of the air.

For clarity a preferred cam relationship is'illustrated in Fig. 5. As indicated, in'eachrevolution of the shaft 87 causing the carriage to reciprocate forwardly and rearwardlythe full suction is on from just priortothe beginning of the forward stroke to near the end of the forward stroke representing an angular distance ofabout For the nextangular distance 0f 15 the suction is gradually released and for :''the next angular distance-of 15 'the air pressure'isgradually applied. At this point the carriage starts it's'rearward stroke and full air-pressure remains on for'an angular distance of about 180. For the next angular distance of 15 the air pressure is gradually released and'for the next angular distance of 15 the suction is gradually applied. After full suction grip has been attained the cycle again commences with the carriage moving forwardly with another sheet or blank. It should be noted that the followers 84 and 113 are spaced an angular distance of about 90 apart thus accounting for the relative positions of earns 86 and 115 relative to each' other in the drawings. There are'60 high and low sections of path cam 86 to, permit a dwell at each opposite end of the stroke of the carriage and it is during the dwell, just before the feed stroke, that suction is applied.

I claim:

1. Apparatus for automatically and successively sliding individual sheet fro'rn'the bottom of a stack of'such sheets saidapparatus including bottom feed magazine means for supporting a stack of sheets; sheet separator means including a sheet passage positioned along the leading edgeof the bottom sheet of said stack for permitting the'advance of a single bottom sheet while barring the advance of the-next succeeding sheetsin the stack; friction feed means including afriction surface,v having a plurality of air openings therein, for engaging the'opposed flat undersurface of a bottom sheet and mechanism for reciprocating said surface forwardly and rearwardly relative to said passage rectilinearly in a plane parallel to the plane of said undersurface and with a substantial forward and rearward end dwell; suction means cooperable with said friction feed means, including valve mechanism applying full air suction in said air openings, during said rearward end dwell and continuously for a predetermined major portion of the forward travel of said :friction surface and pneumatic means cooperable with said friction feed means including valve mechanism applying full air pressure in said air openings during said forward end dwell and continuously during the rearward :travel of said friction surface.

2. Apparatus as specified in claim 1 wherein said friction feed means includes a carriage slideable on tracks :spaced below and parallel to the plane, of said bottom .sheet, said carriage supporting a plurality of suction cups, each having an air opening surrounded by a rim of friction material.

3. Apparatus as specified in claim 1 wherein said :friction feed means includes a plurality of suction cups :mounted on a rectilinearly movable carriage, a pivoted bell crank lever for moving said carriage forwardly and :rearwardly and a rotating path cam for pivoting said llever.

4. Apparatus as specified in claim 1 wherein said 'valve mechanism of said suction means and air pres- :sure means comprises a common two way valve connect- :ing said openings to a source of suction and a source of :air pressure, said valve being operably connected to the :reciprocating mechanism of said friction feed means.

5. Apparatus as specified in claim 1 wherein the mechanism for reciprocating said surface includes a rotating shaft and the valve mechanism of said suction means and pneumatic means comprises a common control valve operated by the rotation of said shaft.

6. Sheet feeding apparatus for sliding each successive bottom sheet from an upstanding stack of fiat sheets, said apparatus comprising bottom feed magazine means including a plurality of laterally spaced, longitudinally extending bottom members for supporting a stack; sheet separator means positioned along the leading edges of the sheets of said stack and forming a forward wall of said magazine means for permitting the forward sliding advance of only each successive bottom sheet of a stack; sheet engaging means including a substantially flat friction surface, having air openings therein, said surface being located in a longitudinally extending space between said bottom members and being at the level of, and in engagement with, the undersurface of the bottom sheet in the stack;.sheet feeding mechanism supporting said sheet engaging means and moving rectilinearly, parallel to the plane of a bottom blank, toward and away from said sheet separator means; air suction means, including valve mechanism, connected .to the air openings in said surface and adapted to apply full suction for increasing the frictional adherence of a bottom sheet with said sur face just before, and maintaining full suction during a predetermined major portion of, the movement of said mechanism toward said separator means and pneumatic means, including valve mechanism, connected to the air opening in said surface and adapted to continuously apply full air pressure for decreasing the frictional adherence of a bottom sheet with said surface just before and during the entire movement of said mechanism away from said separator means v 7. Insheet feeding apparatus of the type having a bottomfeed magazine and sheet separator means, the combination of a plurality of sheet segregating suction cups continuously reciprocating forwardly toward said sheet separator means. and. rearwardly away from said sheet separator means, said cups having co-planar sheetengaging faces at the level of the bottom of the magazine, air suction means, synchronized with the reciprocating movement of said cups said means including a valve applying full suction in said cups from the beginning to near the end of the forward stroke thereof and pneumatic means, synchronized with the reciprocating movement of said cups, said means including said valve and applying full air pressure in said cups throughout the rearward stroke thereof.

8. Blank feeding apparatus for feeding individual blanks successively from the bottom of stack of blanks, said apparatus including a plurality of spaced apart suction grippers in engagement with the underface of the bottom blank of a stack and at least partially supporting said stack; feeding mechanism supporting said suction grippers while continuously reciprocating the same in a plane parallel to the planes of said blanks; air suction means, including a control valve operated by said feed mechanism, for exhausting air at full suction, from said grippers from the beginning to near the end of the forward stroke thereof and pneumatic means including said control valve for blowing air, at full pressure, through said grippers on the entire rearward stroke thereof.

9. In sheet separating apparatus the combination of a sheet feeding member having a friction surface with spaced air openings therein, means for reciprocating said member in a plane parallel to the plane of a sheet with said friction surface bearing against an exposed face of said sheet; air suction means for creating suction in said openings; pneumatic means for blowing air out through said openings and valve means, operably connected to said reciprocating means for actuating said suction means at full suction from the beginning to near the end of the forward stroke and actuating said pneumatic means at full pressure on the entire rearward stroke of said sheet feeding member.

10. In sheet feeding apparatus having a bottom feed magazine the combination of a plurality of suction grippers each having friction faces co-planar with the bottom of the magazine; a carriage supporting said grippers at said level and slideable on tracks parallel to the plane of the bottom of said magazine; a bell crank lever pivotably mounted below said carriage, one arm of said lever being connected to said carriage and the other arm of said lever having a cam follower; a continuously rotating cam having a path for said follower, said cam thereby continuously reciprocating said carriage; suction means including a source of suction, a control valve and conduits leading from said control valve to said suction grippers; air pressure means including a source of air pressure and said control valve and a cam rotatable with said path cam for actuating said control valve to apply full suction in said grippers continuously during the major portion of the forward reciprocation of said carriage and to apply full air pressure in said grippers continuously during the rearward reciprocations of said carriage.

11. The method of frictionally feeding individual end sheets successively from a stack of fiat sheets with suction grippers which comprises the steps of moving the suction grippers in the plane of the exposed surface of an endmost sheet along a forward feeding path while air is exhausted from said grippers, continuously at full suction, from the beginning to near the end of said path to increase the frictional contact thereof and returning the suction grippers in the plane of the exposed surface of an endmost sheet along the same said path while air is blown out of said grippers continuously at full air pressure throughout said path to decrease the frictional contact thereof. 

